It is the two last we have an interest in as these represent the live distro, try doing the df -h without having the stick mounted if you don't know the names of the mountpoints.

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Now unmount the USB stick.

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===== Copy the live USB stick to an ISO =====

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Once unmounted you are going to use the infamous dd command ( DO NOT DO THIS UNLESS YOU ARE ABSOLUTELY CERTAIN WHAT YOU ARE DOING AS YOU CAN WREAK HAVOC WITH YOUR SYSTEM IF YOU MESS UP, DOUBLE CHECK AND TRIPLE CHECK EVERY DD COMMAND YOU MAKE!!! )